Integral drip irrigation emitters, whose surface areas are adapted for affixing onto the inner wall of the hose, are well known and recognized, wherein water exit “pool” (also known as water outlet basin) is formed on them. Naturally, a water outlet opening that, as said, is formed on its side in the hose's wall, is formed opposite said water exit “pool” and within its boundary, wherein it connects for water flow passage from it to the outer side of the hose and thus enables the exit of the water from the integral drip irrigation emitter to the outside of the hose.
For the sake of clarification, it is specifically noted herein under that using the term ‘hose’ does not limit in any way whatsoever the thickness of the wall of the hose (pipe) and that integral drip irrigation emitters are installed (implemented) inside hoses having thin walls thickness as well as in hoses with thick walls dimensions, wherein the hoses can be manufactured in varied manufacturing technologies (for example by extrusion of a tubular profile or as a sheet that is folded and rolled to become tubular and then welded as a “seam” all along its length dimension).
Concurrently, in the irrigating by dripping field, an elongated slit (one or more) is known and recognized as a configuration of a water outlet opening that is different for example from drilling a round bore shape opening at the hose's wall.
See for example U.S. Pat. Nos. 3,293,861 and 4,053,109 that describe slits as the exit opening from hoses (hoses in general, not drip irrigation hoses).
From the outset, forming a water outlet opening specifically as a slit and in a directional orientation with the length-wise dimension of the hose, facilitates to exploit the possibility to integrate the necessary stage of forming the water outlet opening, in a continuous (sequential) production process in which the hose is in motion all the time, and compare—the simplicity of the timed lowering of a slit-cutting blade into the non-stopping continuous movement of the hose, as opposed to the complexity of the necessity to propel drilling means to the hose's side, concurrently with the endless movement of the hose and in synchronization with the non-stopping advancing movement of the hose until completing the drilling of a round opening type of an outlet opening.
See for example patent IL 105,745 wherein there was displayed a means for creating outlet openings from a drip irrigation hose of the “tape” type (different from drip irrigation hose in which discrete drip irrigation units are integrated), in a configuration of a knife that is lowered from time to time onto the flow of the hose (and naturally produces a slit as a water outlet opening from it)—see there FIGS. 19-21.
To continue and in referring to drip irrigation hoses of the “tape” type, to which it is actually referred as of a continuous strip of drip irrigation emitters that is affixed to the wall of the hose or formed as an integral part of it, a possibility of forming water outlet openings was described wherein the water exits are exactly thin slits (while avoiding as much as possible extracting material from the hose wall in the process).
See for example U.S. Pat. Nos. 5,522,551 and 5,865,377 that described a thin and long slit, with the capability of self-opening and self-closing as the water outlet opening from drip irrigation hoses of the “tape” type (as differentiated from an integral drip irrigation hose in which discrete drip irrigation emitters are integrated).
Professionals have learned that forming the water outlet as a thin and elongated slit might contribute to decreasing the phenomena of clogging the water exit openings that result from penetration of earth lumps, dirt, contamination or roots (that naturally are pulled towards the water outlet openings from the hose and grow towards them). Integral drip irrigation hoses can be buried in the ground (for ensuring fast wetting and to prevent their movement in high winds). Embedding the hoses in the ground is liable to worsen the clogging problem when the water pressure in the hose is reduced. It causes suction inwards phenomena of foreign objects (soil and the like). Hence, forming the water outlet opening at the wall of the hose, in the configuration of an elongated very thin slit, in accordance with the hose wall thickness, may lead to the result that when the water pressure decreases the slit would “close itself” in a manner that can prevent penetration of foreign objects at the time the suction phenomenon starts.
Thus it has been known to form the water outlet opening in the configuration of a thin and extended slit, but this configuration has been implementable only in drip irrigation hoses of the “tape” type whose wall was relatively thin and wherein the configuration of the water pressure reduction mechanism (for example—as an elongated continuous strip of drip irrigation emitters), enables—in geometrical terms, to allocate a substantial length as required, for the slit formation.
However, when we consider an integral, discrete drip irrigation emitters, that are formed, each one of them, with a water exit “pool”, we will find that from the outset the length dimension of the exit “pool” limits the possibility to implement at the wall of the hose, a slit that would be at appropriate length given the length dimension of the pool. Hence, the professionals were required to challenge forming an integral discrete drip irrigation emitters with a relatively long exit pool (such a drip irrigation emitter constitutes the subject matter of patent application PCT/IL2012/050115 of the applicant of this current patent application).
Moreover, from the instant of affixing the circumferential rim of the “walls of the pool” of the discrete drip irrigation emitter to the internal wall of the hose (for example—in a way of inserting the drip irrigation emitter into the hose, during the continuous process of manufacturing the hose by extrusion, and affixing it to the still hot hose being extruded, by heat soldering), the drip irrigation emitter body which is relatively rigid, actually insulates the hose's wall sector that is framed and delineated by the circumferential rim of the “walls of the pool”.
Framing and delineating the sector of the circumferential rim of the wall of the hose that is positioned facing the exit “pool”, is found to actually neutralize the influence of the increase of the water pressure in the hose for that relevant sector. Namely, it was found that increase or decrease of the water pressure prevailing in the hose, does not any longer cause an elastic deformation in the hose wall sector that is framed and delineated by the circumferential rim of the “walls of the pool”.
Thus, until the invention that is the subject matter of this application, professionals in this field that wanted to obtain the advantages inherent in the elongated slit as the water outlet opening, which we pointed above, and this—also in the configuration of a drip irrigation hose in which there are installed integral, discrete drip irrigation emitters, found that from the instant that they affixed integral drippers with an exit “pool” to the thin wall of the hose, they actually neutralize the elastic properties of the thin wall of the hose, which they need for obtaining the same advantages.
Affixing the circumferential rim of the “walls of the pool” in an integral drip irrigation emitter that is relatively rigid onto the wall of the hose, actually neutralized the hose sector that is found framed and delineated by the same walls, from the influence of the increase or decrease in the water pressure in the hose. The radial forces on the wall of the hose, which were activated by the increase of the water pressure, were not “translated” for the task as properly required, to pulling the hose wall sector that is framed and delineated by the circumferential rim of the water exit “pool” on its two sides.
Not withstanding, and to differentiate from the elastic swelling (becoming inflated) and flattening of the hose profile in accordance with the increase and decrease of the water pressure in it, as was carried out due to the soft raw material from which the hose is commonly manufactured (for example, polyethylene) and its relatively thin wall thickness, the relatively rigid construction of the integral (discrete) drip irrigation emitters (that are commonly manufactured by injection of a relatively rigid polymer), absorbed the strain without resulting in the required elastic deformation due to puling the wall of the hose sector that is framed and delineated by the circumferential rim of the water exit “pool” on its two sides.
For clarifying, reference is being made to FIG. 1. The figure includes two pairs of schematic drawings that present the failure of the slit mechanism from the instant of affixing integral drip irrigation emitters and framing and delineating a sector of the walls of the hose opposite the exit “pool” of the drip irrigation emitter.
The first pair (1a) represents by a cross section, a hose 10 (without drip irrigation emitters) wherein in its wall there was formed a water outlet opening in a thin slit configuration 20. From the instant of water pressure dropping in the hose, the hose is flattened and the opening of the slit is closed. upon rise of the water pressure in the hose (P), radial forces are exerted on the inner wall of the hose (marked by arrows) that cause the swelling (inflating) of the hose and due to it also creating a local inflating in the area in which the slit 20 is formed, and as a result—to the opening of the slit for water passage outwards (see the opening width dimension of the slit that was marked W).
The second pair (1b) depicts by a cross section, a hose 30 with a “boat” like integral drip irrigation emitter 40 affixed to its inner wall. Drip irrigation emitter 40 is formed with a water exit “pool” 50 on its surface area that is turned towards the wall of the hose, in such a manner that it instills to the cross-section of the drip irrigation emitter a characteristic appearance as the letter U (wherein its “legs” 52 and 54 are formed at their ends with a rim that constitutes a part of a circumferential rim 57 of the water exit “pool” 50 and “legs” 52 and 54 are linked by what constitutes the “bottom” 59 of the water exit “pool” 50). From the instant of integrating the drip irrigation emitter inside the hose (as shown in the figure), the edge of the circumferential rim 57 of water exit “pool” 50 is affixed to the inner wall of hose 30. From the instant of affixing circumferential rim 57 (for example—by heat soldering while manufacturing the hose by extrusion), it frames and delineates a sector of the wall of the hose (see the width dimension of the sector that was numbered 60). As control of the opening and closing of the water outlet opening in accordance with the pressure that prevails in the hose is required (while exploiting the elasticity characteristic of the material of the hose), there is implemented a water outlet opening in the configuration of a thin slit 70. In this case too, with the increase of the water pressure in the hose (P), there are exerted radial forces on the inner wall (marked by arrows) that cause the swelling (inflating) of the hose, but the relatively rigid profile, in the shape of the letter U of the drip irrigation emitter 40 absorbs the strain without resulting in providing elastic movement of pulling the wall sector of the hose, that is framed and delineated by circumferential rim 57 of the water exit “pool”, in its width dimension 60 on its two sides. Therefore, slit 70 remains closed as it was.
In this situation, at most, inside the water exit “pool” and under the sector of the wall of the hose that is framed and delineated by the circumferential rim of the “walls of the pool”, drops of water are accumulated—in which there prevails approximately the atmospheric pressure (as an outcome of passage of water through the water pressure reducing mechanism in the drip irrigation emitter). Such an accumulation of drops, is not enough to expose the sector of the wall of the hose for a strain that would lead as required to an elastic deformation of “opening” the slit for a passage of water, namely dynamically and in correlation with the increase of the water pressure in the hose and to “closing” the slit for water passage from the instant of decreasing water pressure in the hose (and at most there will be a trickling of water through the slit opening).
Indeed, it is feasible to design a slit that would open a little from the instance of accumulation of a sufficient water pressure in the exit “pool”, but in such a scenario the varying differential pressure prevailing between the “pool” and beyond the wall of the hose—in the environment, constitutes an additional resistance (accumulating in series) to that that was posted by the pressure reducing means (for example—the labyrinth) in the drip emitter. The flow rate from the dripper would hence be dependent also on the resistance to the flow presented by the slit (a resistance that can vary in accordance with, for example, the thickness of the wall of the hose, environmental temperature and so on), and this creates difficulties in achieving accurate design (planning), (for example, would necessitates increasing the minimal working pressure of the drip emitter or would mandate forming a relatively long slit).
U.S. Pat. No. 7,681,805 describes forming water exit openings in a configuration of slits in an integral drip irrigation hose in which there are integrated discrete drip irrigation emitters. A publication of patent application WO 2011051936 describes forming a shaped water outlet in a drip irrigation conduit in which there are integrated discrete drip irrigation emitters. But, as said, in the cited publications, there is not described any means what so ever that enables dynamically opening a slit to water passage through it, and hence the conclusion, by straightforward logic, is that actually the prevailing water pressure in the water exit pool (namely—atmospheric pressure), is the only means for opening of the water outlet, or in other words—these publications depict a water exit opening that is not dynamic (i.e., an opening that does not behave according to and in correlation with the water pressure that prevails in the hose).
U.S. Pat. No. 7,175,113 describes an integral drip irrigation hose with control capability over the exit openings from it in accordance with the prevailing water pressure in it, but what is treated there are configurations of “a kind of” unidirectional valves with clearly a complex construction. Thus for example, in one configuration (see there, FIGS. 19 and 19a to-19e), a bi-component construction, made of two different materials and a complicated angular geometry of the water passage is described. In a second configuration (see FIGS. 20 and 20a to 20c), once again—a rather complicated bi-components construction made from two different materials and providing the opening area with a slack addition that enables local swelling (inflating) of the hose is described.
Furthermore, the functioning of the unidirectional valves mechanisms that are described there, depend on the wall thickness of the specific hose, and hence requires compatibility and design anew in accordance with the wall thickness of the hose. Moreover, a bi-components structure is deemed to be relatively expensive, limited by the variety of materials that can be used (selected) (the two materials have to be suited to co-extrusion manufacturing process), and the elastomeric component might be harmed by creep during long service and also due to temperature variations.
As per these circumstances, in the time that preceded the current invention, a need for integral, discrete, drip irrigation emitters with an exit “pool” formed on them existed, that would enable in a simple and relatively low priced manner, utilizing a water outlet opening on the wall of the hose into which they are integrated, that would be not only formed as a slit relatively long and thin, but also provide for dynamic “opening” and “self closing” capabilities, in accordance with the water pressure prevailing in the hose and in correlation to it.